[Measurement of effective hepatic blood flow using 99mTc-PMT SPECT and single blood sampling]

Effective hepatic blood flow (EHBF) was measured from an uptake constant using single blood sampling and 99mTc-PMT hepatobiliary SPECT data. After intravenous injection of 3 mCi (111 MBq) of 99mTc-PMT, serial 1 min SPECT data were obtained for 7 minutes. A time activity curve (TAC) over the heart, that was normalized with the 5 minutes venous sample concentration (%/dose/ml), was used as a blood clearance curve (B(t]. And a TAC of the whole liver, that was normalized with the injected dose of 99mTc-PMT (%/dose), was used as a hepatogram (L(t]. An uptake constant representing EHBF, was estimated from the Rutland's method L. (t)/B(t) was plotted against integral of otB(t)dt/B(t), and the slope of the least square fitted straight line was determined as the uptake constant. In 16 cases, significant correlation was obtained between the 99mTc-PMT hepatic uptake at 5 minutes and the EHBF estimated from the blood clearance (r = 0.85, p less than 0.001). While there was a much better correlation between the EHBF from uptake constant and the EHBF from blood clearance (r = 0.95, p less than 0.001). In conclusion, this analysis for uptake constant of 99mTc-PMT SPECT data enables us to estimate EHBF with single venous sampling and in relatively short acquisition time. This method is thought to be very valuable in clinical practice.